The Effects of an Acidic River, Caused by Acidic Rain, on Weight Gain, Steroidogenesis, and Reproduction in the Atlantic Salmon (

Author(s):  
HC Freeman ◽  
GB Sangalang
1990 ◽  
Vol 47 (12) ◽  
pp. 2422-2430 ◽  
Author(s):  
G. B. Sangalang ◽  
H. C. Freeman ◽  
J. F. Uthe ◽  
L. S. Sperry

Attempts to avert the impacts of an acidic river environment on Atlantic salmon (Salmo salar) were carried out in 1985 and 1986. Salmon were held in the Westfield River (pH 4.7–5.2) and the nearby Medway River (pH 5.3–5.6) during their sexual maturation. A diet containing 3% NaCl was fed to the Westfield salmon in 1985. Marble chips were used to elevate the pH of Westfield River water in 1986. Fish fed the salt diet had higher peak levels of plasma sex hormones, higher fecundity, greater incidence of spawners, lower egg mortality, and less weight loss than fish fed a commercial trout diet. The reproductive performance of fish held in limed water (pH 5.1–5.9) almost attained the level observed in the Medway (control) fish. Limestone treatment stimulated early peaking of blood androgen levels, testosterone, and 11-ketotestosterone in Westfield males, and 17α, 20β-dihydroxy-4-pregnen-3-one, a follicular mediator of gonadotropin, in a few Westfield females. The head kidneys produced more cortisol and corticosterone in all Westfield fish in both years compared to Medway fish. The results suggest that neither dietary salt nor liming completely prevented the decline of reproductive performance and the alteration of steroid hormone metabolism in salmon.


1989 ◽  
Vol 46 (11) ◽  
pp. 2003-2018 ◽  
Author(s):  
Gilles L. Lacroix

Densities, growth, and production of juvenile Atlantic salmon (Salmo salar) were estimated at sites in two acidic rivers of different pH, the Westfield and North rivers, in Nova Scotia, Canada, from 1982 to 1984. Annual production was significantly lower in the more acidic Westfield River (< 0.4 g∙m−2∙yr−1 at pH 4.7–5.4) than in the North River (1.4 g∙m−2∙yr−1 at pH 5.6–6.3). Low production rates in the more acidic river were attributable to the lower densities and poorer survival of juveniles at the lower pH levels. Low densities of parr in the more acidic river were a function of the high initial mortality of postemergent fry, and the mortality of parr during periods of pH minima such as over winter. Marking and recapture information and trapping at a weir for counting migrating fishes indicated that there was little emigration of parr other than in the spring when some movements occurred preceding and during smoltification. Average potential yield of 2-yr smolts was 0.8 smolt/100 m2 in the Westfield River and in the range of 2.7–6.6 smolts/100 m2 at higher pH levels in the North River. Growth was not limiting to production at the lower pH levels. After the first winter, 1-yr-old parr were much larger at the lower pH than they were at less acidic pH levels, the faster growth possibly resulting from the lower density of parr at the lowest pH. A temperature-related biphasic growth of 1-yr-old parr with periods of maximum growth in spring and autumn was recorded. Reduced production, a result of deleterious effects of low pH on survival and density in the Westfield River was probably sufficient to prevent the continued maintenance of a naturally produced salmon population in that river, whereas production at higher pH levels in the North River was comparable to that in near-neutral waters of other areas.


Biomolecules ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 845
Author(s):  
Nina N. Nemova ◽  
Zinaida A. Nefedova ◽  
Svetlana N. Pekkoeva ◽  
Viktor P. Voronin ◽  
Natalia S. Shulgina ◽  
...  

The influence of two light regimes, 16:8 h light/dark (LD 16:8) and 24:0 h light/dark (LD 24:0), in comparison to a usual hatchery light regime (HL), on the fatty acids content and weight gain in hatchery-reared underyearlings (at 0+ age) and yearlings (at 1+ age) of Atlantic salmon in the summer–autumn period was studied. The total lipids were analyzed by Folch method, the lipid classes using HPTLC, and the fatty acids of total lipids using GC. The increase in EPA and DHA observed in October in underyearlings and yearlings salmon (especially under LD 24:0) suggests they were physiologically preparing for overwintering. The changes in fatty acids and their ratios in juvenile Atlantic salmon can be used as biochemical indicators of the degree to which hatchery-reared fish are ready to smoltify. These associated with an increase in marine-type specific DHA and EPA, an increase in the 16:0/18:1(n-9) ratio, in correlation with a reduction in MUFAs (mainly 18:1(n-9)). These biochemical modifications, accompanied by fish weight gain, were more pronounced in October in yearlings exposed to continuous light (LD 24:0). The mortality rate was lower in experimental groups of underyearliings with additional lighting. Exposure to prolonged and continuous light did not affect yearlings mortality rate.


1986 ◽  
Vol 43 (10) ◽  
pp. 1888-1893 ◽  
Author(s):  
B. O. Rosseland ◽  
O. K. Skogheim ◽  
H. Abrahamsen ◽  
D. Matzow

Smolts of Atlantic salmon (Salmo salar) were exposed for 70 h in the acidic River Vaaraana, southern Norway (Q = 1.3 m3/s, pH = 4.4–5.6, Ca = 0.6–1.5 mg/L, labile Al = 50–100 μg/L), to waters neutralized by addition of limestone slurry. Chemical and biological parameters were measured upstream of the liming site and 20, 100, 1000, 2000, and 3500 m downstream. Addition of limestone slurry effectively increased pH from 4.6 to 6.9, Ca from 0.6 to 2.6 mg/L, and reduced the labile Al concentration from 59 to 35 μg/L immediately downstream of the liming site (20 m, after 30 s). In the untreated upstream waters, salmon smolts lost plasma Cl rapidly, and all fish died within 36 h. In spite of the slight oversaturation of labile Al immediately downstream of the base addition, no mortality occurred in neutralized waters. Relatively high Ca concentrations may have mitigated potential toxic effects from Al oversaturation. Plasma Cl levels did not vary with distance downstream. Detoxification of running waters with highly toxic levels of pH and Al can successfully be performed by addition of limestone slurry.


1999 ◽  
Vol 56 (11) ◽  
pp. 2078-2086 ◽  
Author(s):  
Frode Kroglund ◽  
Magne Staurnes

Groups of Atlantic salmon (Salmo salar) smolts were held 1-13 days in soft water with a pH range of 5.0-6.6, concentrations of labile inorganic monomeric Al (Ali) of 10-90 µg·L-1, and 0.7-2.3 mg Ca·L-1. Fish were exposed to either naturally acidic water from a river in southwestern Norway, limed water from the same river, mixtures of acidic and limed river water, acidic river water with sulfuric acid and Al added, or limed river water with additional lime. Mortality was observed in all groups exposed to water with pH < 5.8 and containing 30-90 µg Ali·L-1. No fish died in water with pH > 5.8 and 15-20 µg Ali·L-1, but fish in water with pH 5.8-6.2 had lower plasma Cl- concentration and gill Na+,K+-ATPase activity than fish in water with pH > 6.5. Smolts exposed to pH < 5.8 were unable to survive in seawater, and smolts exposed to water with pH 5.8-6.2 had lower hypoosmoregulatory capacity than smolts exposed to water with pH > 6.5. These results show that even moderately acidified water with low Al concentrations impairs smoltification and reduces the seawater tolerance of Atlantic salmon smolts.


2012 ◽  
Vol 109 (8) ◽  
pp. 1508-1517 ◽  
Author(s):  
Anita R. Alvheim ◽  
Bente E. Torstensen ◽  
Yu Hong Lin ◽  
Haldis H. Lillefosse ◽  
Erik-Jan Lock ◽  
...  

Dietary intake of linoleic acid (LA) has increased dramatically during the twentieth century and is associated with a greater prevalence of obesity. Vegetable oils are recognised as suitable alternatives to fish oil (FO) in feed for Atlantic salmon (Salmo salarL.) but introduce high amounts of LA in the salmon fillet. The effect on fish consumers of such a replacement remains to be elucidated. Here, we investigate the effect of excessive dietary LA from soyabean oil (SO) on endocannabinoid levels in Atlantic salmon and mice, and study the metabolic effects in mice when SO replaces FO in feed for Atlantic salmon. Atlantic salmon were fed FO and SO for 6 months, and the salmon fillet was used to produce feed for mice. Male C57BL/6J mice were fed diets of 35 % of energy as fat based on FO- and SO-enriched salmon for 16 weeks. We found that replacing FO with SO in feed for Atlantic salmon increased LA, arachidonic acid (AA), decreased EPA and DHA, elevated the endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA), and increased TAG accumulation in the salmon liver. In mice, the SO salmon diet increased LA and AA and decreased EPA and DHA in the liver and erythrocyte phospholipids, and elevated 2-AG and AEA associated with increased feed efficiency, weight gain and adipose tissue inflammation compared with mice fed the FO salmon diet. In conclusion, excessive dietary LA elevates endocannabinoids in the liver of salmon and mice, and increases weight gain and counteracts the anti-inflammatory properties of EPA and DHA in mice.


Sign in / Sign up

Export Citation Format

Share Document